Screwdrivers, as common hardware, are used for fastening or unscrewing screws. The existing screwdrivers generally mainly consist of a handle, a bar and a tip. A user rotates the handle to drive the bar and the tip to rotate. In this way, a screw is fastened or unscrewed by driving the screw by the tip to rotate. However, the rotation of such screwdrivers depends completely on manpower, it is manpower-consuming to use and also difficult to control the direction. Gyration might be caused during the rotation, thus making it more inconvenient to use.
To overcome the defects above, there are some ratchet screwdrivers capable of idling in a single direction. For example, in Chinese Pat. No. 201020222335.5 titled “RATCHET SCREWDRIVER”, the ratchet screwdriver includes a ratchet rod, a hollow control rod and a sleeve; a front portion of the ratchet rod is a cavity connecting a tip of an external screwdriver, a middle portion is a ratchet component, and a rear portion is a connecting portion; a front portion of the control rod has a projecting portion, and a rear portion thereof is a connecting rod; the connecting rod of the ratchet rod and the ratchet component are inserted into the control rod and located at the projecting portion and the connecting rod respectively, the ratchet component is partially surrounded by the projecting portion, and the ratchet rod can be inside the control rod and rotate with respect to the control rod; and the sleeve is sleeved outside the projecting portion and the ratchet component to form a ratchet mechanism for controlling the idling in a single direction and locking of the screwdriver. However, this ratchet screwdriver rotates at a 1× speed, and is thus less manpower-saving.
In Chinese Pat. No. 201310505585.8 titled “RATCHET SCREWDRIVER ROTATING AT A MULTIPLIED SPEED”, the screwdriver handle includes a tip, a handle, an extension rod, a ratchet device and a multiplied rotation device; the ratchet device includes a ratchet body, a ratchet ring, a ratchet roll pin and a hollow shaft; the multiplied rotation device includes a gear seat, a clutch gear, a big planetary gear and an external housing, and the ratchet device and the multiplied rotation device are connected by a gear shaft; and the ratchet device is fixedly arranged on the handle, one end of the extension rod is fixedly connected to the gear shaft, and the tip is fixedly arranged at the other end of the extension rod. Since such a screwdriver handle can transfer a multiplied rotation speed, the speed for screwing a screw is greatly increased. It can be designed to rotate at a 4× speed as the existing multiplied ratchet screwdrivers. However, since gears 13-14 as shown in the drawing are all idler gears which do not rotate with the handle, such a screwdriver can rotate at a 4× speed to the maximum; and if this screwdriver is designed with a higher speed, for example, a 5× speed, it is necessary to expand the overall external diameter of the ratchet structure, and in doing so, it is inconvenient to carry and use such a screwdriver. This screwdriver is not ideal in the structural design. At present, there is no report about a ratchet screwdriver that rotates at a speed higher than 4×.